2 Understanding Oracle WebCenter

2.3.1 Portlets and Pagelets for Accessing Remote Applications and Services

This section discusses two technologies–portlets and pagelets–that let you integrate remote applications into your portal pages.

• Section 2.3.1.1, "What Are Portlets?"

• Section 2.3.1.2, "What Are Pagelets?"

2.3.2 Oracle Composer Allows User Customization

Oracle Composer is an easy, browser-based environment that you can add to existing JSF applications. End users can then use Oracle Composer to edit the page at runtime to create their own mashups. To make pages editable at runtime in this way, you simply add Oracle Composer design time components to a page in JDeveloper. If you create a blank page in JDeveloper with just Oracle Composer components, users have the ability to redesign the page while in Edit mode using Oracle Composer. Some of the tasks they can perform include:

• Editing page settings and parameters

• Adding content to the page

• Editing component properties and parameters

• Wiring components to page parameters

• Arranging content on the page

• Changing the layout for components on the page

• Removing components from the page

The Oracle Composer tag library provides the components that you can add to make a page editable at runtime and define the behavior of content on the page (for example, move, sequence, or hide components).

In Oracle Composer, the Component Catalog dialog box, which is displayed by clicking the Add button on the page, displays the default runtime Resource Catalog Viewer. Users can browse the components in the viewer and then add them to the page. By default, the viewer displays the default Resource Catalog, which contains all of the Oracle ADF components and portlets available to the application. To control what components are visible to users in the viewer, you can modify the default Resource Catalog, or create one or more of your own Resource Catalogs. Resource Catalogs can contain items such as portlets, layout components, task flows, documents, and Oracle ADF Faces components.

For more information about implementing Composer components in your application, see Chapter 19, "Enabling Runtime Editing of Pages Using Oracle Composer."

2.3.3 Content Integration with Supported Content Repositories

JCR (Java Content Repository API, also known as JSR 170) adapters enable you to make data stored in content management systems, such as Oracle Universal Content Management, Oracle Portal, or even your file system, available to your application.

Using JDeveloper, you can use the prebuilt JCR data control to grab the content and drop it onto your page. You can leverage the provided prebuilt user interface to display the content in your WebCenter Portal application. This architecture enables you to build your user interface once and then at deployment time or during runtime, switch to whatever back end is required without having to recompile or rebuild the application. In addition, you do not need to learn the intricacies of each content management system's custom APIs. For example, you could create a data control that selects content from any JCR 1.0 compliant repository or file system. When the data control is created, you can drop it onto a JSP document as a table.

If you retrieve data from a content repository other than Oracle Portal, UCM, or the file system, then you can create your own JCR adapter. From the Content Repository Configuration page of the Create Data Control wizard, you can choose the content repository from which you want to retrieve data.

The Content Presenter task flow lets you conveniently add content to your application. Content Presenter allows you to select a single item of content, multiple content items, or query for content, and then select a template to render the content on a page in a WebCenter application. In addition, you can design custom display templates for Content Presenter. See Chapter 28, "Creating Content Presenter Display Templates." For more information, see also "Adding Content Using Content Presenter" in the Oracle Fusion Middleware User's Guide for Oracle WebCenter Spaces and Chapter 26, "Configuring Content Repository Connections."

2.3.4 Search Framework

Search is one of the most common and useful features of any web application. Oracle WebCenter Framework has a unified, extensible Search framework that enables the discovery of information and people through an intuitive user interface. The powerful Search framework enables you to seamlessly include enterprise-wide search capabilities into your application. With all relevant and secure information easily navigable, users do not need to switch between applications performing multiple searches. See Chapter 40, "Integrating the Search Service."

2.3.5 Resource Catalogs Help Organize the Development Experience

The Resource Catalog provides a federated view of the contents of one or more otherwise unrelated repositories within a unified search and browse user interface. Resources are created and published in their source repository, then exposed to the developer through the JDeveloper Resource Palette and to the end user through the Resource Catalog Viewer. The Resource Palette contains the WebCenter Portal Catalog, which includes elements that are commonly used in portal development.

Resource Catalogs can contain the following components:

• Layout components. The primary layout component is a Box, which is a container that can hold all other types of components. At runtime, you must have a Box into which you can drag and drop components. You can also add and arrange child components and delete components from a Box.See the Oracle Fusion Middleware Web User Interface Developer's Guide for Oracle Application Development Framework.

• Oracle ADF Faces components. You can add Text, Image, Page Link, Web Page, and Website Link components to your page. These are analogous to the JDeveloper design time components Rich Text Editor, Image, Command Link, Web Page, and Go Link, respectively.

  The Text component enables you to add rich text on the page. Adding this component invokes a text editor that can be resized and is similar to an HTML editor. You can add text and format it using the options available in the editor. See the Oracle Fusion Middleware Web User Interface Developer's Guide for Oracle Application Development Framework.

• Portlets. You can add WSRP, JSF Portlet Bridge Portlets, or PDK-Java portlets from any producer that was registered in JDeveloper. For more information about registering portlet producers and adding portlets to a page, see Chapter 59, "Consuming Portlets."

• Pagelets. The Oracle WebCenter Pagelet Producer (previously known as Oracle WebCenter Ensemble) provides a collection of useful tools and features that facilitate dynamic pagelet development. For detailed information about pagelet development and configuration using the Pagelet Producer, see Chapter 58, "Creating Pagelets with the Oracle WebCenter Pagelet Producer."

• Task Flows. If you have created task flows in JDeveloper, you can add these task flows from JAR files onto your page at runtime. For more information about ADF task flows, see the Oracle Fusion Middleware Fusion Developer's Guide for Oracle Application Development Framework.

• Documents. If you have configured the Documents service in your application, you can add documents from this service. For more information about the Documents service, see Chapter 29, "Integrating the Documents Service."

• Data Controls. Several WebCenter services provide data controls for building a customized user interface with a WebCenter application or task flow. The documentation for each service includes more information about that service's data control. See the Oracle Fusion Middleware Fusion Developer's Guide for Oracle Application Development Framework.

2.3.6 Application Security

With the Oracle ADF extensions provided in Oracle WebCenter, you can define security for an entire application, a page hierarchy, part of a page hierarchy, navigational components, or a single page. You can define security for individual actions provided by customizable components. In addition, for WebCenter Services that connect to back-end servers using web services, you can provide secure identity propagation with WS-Security.

Because Oracle WebCenter security is based on the JAAS and J2EE standards, enterprise roles defined in the existing identity management store can be leveraged directly when securing a WebCenter Portal application. You need not synchronize roles within the application being built. It just references and uses the defined users and roles directly. Note also that you can use file-based security for the development phase of the application and then easily switch over to enterprise identity management at deployment time.

Oracle WebCenter also provides application roles that you can use to represent the policy of an application. By associating permissions with an application role defined within the policy store, you can keep them self contained within the application. On deployment, you can then associate users and enterprise roles with the application roles to grant those permissions to end users.

In some cases, it is desirable to leverage existing applications that have their own authentication mechanism, such as email. The email system is often on a different authentication system (with different user names and passwords) than the new application. The application must map the email user to the application user such that end users do not have to enter their user names and passwords each time they need information. Oracle WebCenter Framework provides the means to securely manage these user names and passwords with the External Application functionality.

For more information about options for securing your WebCenter Portal application, see Chapter 63, "Securing Your WebCenter Portal Application."

2.4.1 WebCenter Services and the REST APIs

You can access many of the WebCenter services through their REST APIs. REST APIs allow you to create rich, interactive client-side applications. REST commands use standard HTTP methods as requests to point to the resource being used. Every request returns a response, indicating the status of the operation. If the request results in an object being retrieved, created, or updated, the response includes a standard representation of that object.

For more information and a complete list of the services that include REST APIs, see Chapter 51, "Using Oracle WebCenter REST APIs."

2.5.1 What Is Oracle ADF?

The Oracle Application Development Framework (Oracle ADF) is an end-to-end application framework that builds on Java Platform, Enterprise Edition (Java EE) standards and open-source technologies to simplify and accelerate implementing service-oriented applications. Used in tandem, Oracle JDeveloper and Oracle ADF give you an environment that covers the full development life cycle from design to deployment, with drag-and-drop data binding, visual UI design, and team development features built in.

2.5.2 Why Is Oracle ADF Important for WebCenter Portal Developers?

You can build portals using a variety of different technologies and approaches, and WebCenter supports a variety of open industry standards for portal-building. Oracle ADF provides a solid foundation for WebCenter portal development, which allows integration with the entire Oracle Fusion Middleware stack. Oracle WebCenter lets you build portals that plug into this overall architecture, leveraging features provided by the rest of the stack.

2.5.3 What Does Oracle ADF Technology Include?

Oracle ADF uses a set of standard JSF components that include built-in Ajax functionality. Ajax is a combination of asynchronous JavaScript, dynamic HTML (DHTML), and XML. This combination allows requests to be made to the server without fully re-rendering the page. While Ajax allows rich client-like applications to use standard Internet technologies, JSF provides server-side control.

Oracle ADF provides over 150 rich components, including hierarchical data tables, tree menus, in-page dialogs, accordions, dividers, and sortable tables. Oracle ADF also provides data visualization components, which are Flash and SVG-enabled and capable of rendering dynamic charts, graphs, gauges, and other graphics that can provide a real-time view of underlying data. Each component also supports skinning, along with internationalization and accessibility.

ADF task flows represent a critical component for you to understand and use in your application development. They provide a modular approach for defining control flow in an application. Instead of representing an application as a single large JSF page flow, you can break it up into a collection of reusable task flows. In each task flow, you identify application activities, the work units that must be performed in order for the application to be complete. An activity represents a piece of work that can be performed when running the task flow. Task flows also have the advantage of being able to be packaged and deployed with the application, rather than requiring a separate deployment like remote portlets. For more information about task flows, see the Oracle Fusion Middleware Fusion Developer's Guide for Oracle Application Development Framework.

2.8.1 User Considerations

The following list suggests questions you should ask about the end users of your portal application:

• How many users are there? If your WebCenter Portal application must serve a large number of users, then you must take that into account when you define your deployment environment.That is, you must choose a topology that can support the number of users you expect to access your WebCenter Portal application and set the configuration parameters of the different services accordingly.

  To help you decide which Oracle Application Server configuration best supports your WebCenter Portal application, see the Oracle Fusion Middleware Enterprise Deployment Guide for Oracle WebCenter.

• Do users need to edit pages and create enterprise mashups by adding resources? If you plan to let users edit pages, you must add Oracle Composer components to your application. You should also consider questions such as which areas you want to make editable and what resources to make available to users.

  When you design your application, you must choose where to insert the Oracle Composer components to make those areas of the page editable. Components that allow users to add to the page must appear in a Resource Catalog at runtime. You can also choose to have different catalogs available depending upon the context of the application or the user's privileges.

  If you choose to allow page editing, the application must be able to associate the customizations with particular users, which means some form of authentication is required for users of the application. Furthermore, since the user's customizations are stored in Metadata Storage (MDS), you must ensure that your deployment system has access to MDS for the storage and retrieval of customizations.

  For more information about the Oracle Composer and exposing resource catalogs, see Chapter 19, "Enabling Runtime Editing of Pages Using Oracle Composer."

• Do users need to customize their portlets? Portlets can optionally include a customization mode (Edit mode) that enables an authenticated user to customize the portlet at runtime. The Edit mode might allow the user to enter things such as the portlet's title or a parameter that affects the content of the portlet. For example, you could implement an Edit mode that enables the user to enter ticker symbols for a stock portlet. When the user's changes are applied, the portlet displays the prices for their chosen ticker symbols.

  If you choose to implement customization, then you must also implement some form of security for the application consuming the portlet. Only authenticated and authorized users can customize an application.

  In considering portlet customization, you should also consider whether the portlets are load balanced. If they are load balanced, then you must use database backed customization to ensure that all of your middle tiers can access to the user's customization data. Otherwise, the user has to personalize the same portlet multiple times.

  For more information, see Chapter 53, "Overview of Portlets."

• Which services do your users need to access? WebCenter provides a variety of services, such as Documents, Discussions, Search, People Connections, and Instant Messaging and Presence. You must decide which of these services your users need and then configure those services. When the desired services are installed and configured, you can add task flows to your application pages that access those services. The services that you choose to implement can also impact the topology you choose. For example, you might choose to have your discussions server and content repositories reside on different systems, which must both be accessible to your application.

  For more information, see Table 2-1, "Oracle WebCenter Services" and Chapter 7, "Preparing Your Application for Oracle WebCenter Services."

• Will there be both authenticated and unauthenticated (public) users? Several of the WebCenter services offer limited functionality for unauthenticated users. For example, unauthenticated users can view but not contribute to discussions, and the REST services (most of them) are only available to authenticated users. Due to this loss of functionality, it sometimes works better to create special public pages designed just for unauthenticated users.

  Use the portal page hierarchy editor to set delegated administration security policies on individual pages or on multiple pages. For more information, see Section 8.5.2, "Securing Your Portal Pages."

2.8.2 Site Administrator Considerations

The following list suggests questions you should ask about the administrators of your application:

• Do administrators need to customize pages and portlets for users or user groups? You may want to enable your WebCenter Portal application administrator to customize pages and portlets to provide default views of the WebCenter Portal application for users.

  • WebCenter Portal application look and feel. By implementing skins for your WebCenter Portal application, you enable administrators to choose the look of the pages in the application.

    For information about how to implement skins, see Chapter 19 "Customizing the Appearance Using Styles and Skins" in Oracle Fusion Middleware Web User Interface Developer's Guide for Oracle Application Development Framework and Chapter 14, "Creating and Managing Skins."

  • Customizable Pages. The administrator can customize the layout of the page.

    For information about customizable components, see Chapter 19, "Enabling Runtime Editing of Pages Using Oracle Composer."

  • Portlets. Portlets can optionally include a customization mode (Edit Defaults mode) that enables the administrator to customize the portlet. The administrator's customization is treated as the default view of the portlet for all other users.

    For more information about portlets, see Chapter 53, "Overview of Portlets."

2.8.3 Developer Considerations

The following list suggests questions you should ask about the developers who will contribute to your application:

• Do developers and administrators want to use the portal framework features in their application? Generally, developers should consider using the Portal Application Template to create portal applications. The template ensures that a new application is provisioned properly with the correct portal framework technology scopes and features. These portal-specific features include page hierarchies, delegated administration, navigation models, and page templates. In addition, runtime administration tools allow authorized users to modify and change these portal features. For more information Chapter 8, "Understanding WebCenter Portal Applications."

• Should developers build task flows or portlets as reusable components? Thanks to the Oracle JSF Portlet Bridge, developers can make their task flows into JSR 286 portlets. Hence, they have the option of creating reusable components either as task flows, which can potentially be made into JSR 286 portlets through the bridge, or directly as JSR 286 portlets. If the primary purpose of the component is inclusion in one or more portals, then developers may prefer to build it directly as a JSR 286 portlet, without going through the bridge. If the primary purpose of the component is local execution in a JSF application, then the developer may prefer to create it as a task flow first and then, optionally, use the bridge to run it as a JSR 286 portlet. Building task flows means that the components can be used in other ADF applications without having to repackage them as portlets first.

• Do developers need to integrate content from content repositories (for example, Oracle Content Server, file system, or Oracle Portal)? If you have content located in content repositories to expose in the WebCenter Portal application, then you must use JCR adapters and data controls to make that content available.

  For information about including content through JCR data controls and adapters, see Chapter 26, "Configuring Content Repository Connections."

• Will the visible/editable content of the WebCenter Portal application vary depending upon the identity of the user? If you plan to have content in your WebCenter Portal application that is not for everyone, then you must set up a security model with login and user roles that enable you to control access. Components, portlets, and pages can display or not display, depending upon a user's identity. If the content is open to everyone (for example, a Human Resources WebCenter Portal application with content for all employees), then you might not need to implement access control. The portal framework page hierarchy feature allows you to set security policies on individual or multiple pages in the page hierarchy. For more information, see Section 8.5.2, "Securing Your Portal Pages."

  Furthermore, with Oracle Composer, you can allow users to edit the content within the application. Again, you must consider whether you want to restrict that capability to certain users and, if so, you must factor that into your security model.

  For more information about implementing a security model for your WebCenter Portal application, see Chapter 63, "Securing Your WebCenter Portal Application."

• Does your WebCenter Portal application need to provide access to external applications? In many cases, you might have external applications to surface in your WebCenter Portal application. For example, you might have email, Human Resources, or financial applications that you would like users to be able to view from within the application. To provide seamless interaction for the user, you must employ an external application credential store of some kind.

  For more information about accessing external applications from your WebCenter Portal application, see Chapter 63, "Securing Your WebCenter Portal Application."

  If you have legacy external application portlets that were built for Oracle Portal, then you can reuse those portlets in a WebCenter Portal application. This feature allows users to view these portlets from their WebCenter Portal application rather than having to open each application separately or go back to Oracle Portal. When building such portlets, though, you must remember that they typically must authenticate themselves to the external application before retrieving and displaying any data. As previously mentioned, such authentication requires a credential vault, where the WebCenter Portal application can store the credentials necessary for logging into the external application. Oracle WebCenter Framework provides choices in Oracle JDeveloper for incorporating portlets based on external applications.

  For more information about external application portlets, see Section 63.13.3, "Managing External Applications."

• Will the WebCenter Portal application be developed by a team of developers? If your WebCenter Portal application is being developed by a team, then you must think about some additional design considerations. For example, when doing team development, you must be much more aware of which files various JDeveloper actions touch, and may want to take advantage of JDeveloper's ability to integrate code management systems.

  For more information about team development, see Chapter 4, "Working Productively in Teams." See also Chapter 1, "Developer's Quick Start Guide."

2.9.1 Generating Accessible HTML

WebCenter provides several Composer components that you can add to your application pages to make them editable at runtime. These components provide attributes that are used to generate accessible HTML. To ensure that the pages you create are accessible, you must set these attributes, listed in Table 2-2.

2.9.2 Accessibility Features at Runtime

When you enable users to customize a page at runtime, you must ensure that any customizations are also accessible to all users. For all components that users can create at runtime, all accessibility-related attributes are shown in the Property Inspector where users can set them appropriately.

For a list of accessibility-related attributes for WebCenter-specific components, see Table 2-2. For a list of accessibility-related attributes for other components, see the Developing Accessible ADF Faces Components and Pages section in the Oracle Fusion Middleware Web User Interface Developer's Guide for Oracle Application Development Framework.

2.9.3 Accessibility Considerations for Portlets

IFrames are not very well accommodated by today's screen readers and so are not permitted by some accessibility standards. Unfortunately, it is a common practice to place nested form tags inside an IFrame. This situation occurs because HTML standards do not allow the use of nested form tags in page content. However, JavaServer Faces pages almost always include a form tag so the JSF reference implementation, which is what is used to generate the markup, puts the entire page body inside a form tag. If you then have a portlet on that Faces page that includes a form tag in its content, which is frequently the case, you have a nested form tag. The common resolution for nested form tags is to put the inner form inside an iframe.

To address the situation of nested form tags and iframes, WebCenter offers two solutions:

• WebCenter automatically parses the HTML markup from portlets looking for form tags and rewrites them and the corresponding submit tags to be Faces compliant using JSF's subform mechanisms. However, this HTML parsing can fail, especially given the growing use of complex, AJAX style markup.

• WebCenter provides an optional attribute in the adf:portlet tag called renderPortletInIFrame. You can set this attribute to false to avoid ever using IFrames.

  • auto (default) - parse the markup and, if the parsing gets an error because it cannot understand it properly, render the content inside an iframe, otherwise render the content inline.

  • true - always render an iframe.

  • false - never render an iframe.